Additionally, we found that the loss of SMAD4 expression was positively correlated with a large tumour diameter (≥ 3 cm), the number of patients with TNM tumour staging (IA~IIA and IIB~IV), lymphatic invasion and poor differentiation, suggesting that the negative expression of SMAD4 in these 95 cases was related to the degree of PDAC malignancy. Here, SMAD4 is linked to neoplasm.